One such suction head presently used comprises a housing 1 made of plastics material, and has a pivotally-mounted suction tube 2 on the back thereof opening out into a well 3 which is integrally molded with the housing 1.
A metal sole plate 4 is fixed beneath the housing 1 by means of screws 5 and together the housing 1 defines a slot 6 through which a retractable peripheral brush 7 may be extended.
Two longitudinal channels 8 and 9 are formed as grooves in the sole plate 4 and are separated by a ridge 10 which does not project quite all the way to the sliding surface of the sole plate 4 so as to enable a small degree of leakage to take place between the two channels.
The front channel 8 is substantially rectilinear, however its cross-section tapers from a middle zone having an aperture 11 towards its ends where it opens out to the sides via passages 12 and 13. In contrast, the rear channel 9 is in the shape of a plane trapezoidal arc having an aperture 14 provided in the central core thereof, and having branches 15 and 16 which are splayed out forwardly and which are closed at their free ends.
The apertures 11 and 14 separated by the ridge 10 open out into the well 3 of the housing 1 and are therefore in communication with the pivoting tube 2, thereby enabling suction appropriate to normal cleaning to be set up beneath the suction head via the channels 8 and 9.
In addition, narrow thread-pickup plates 17 and 18 are permanently fixed, e.g. by gluing, in recesses formed as grooves over a portion of the length of the sole plate 4 along its front and back margins. These pickup plates are covered by cloth having directed fibers and they are positioned so that the fibers are directed towards the apertures 11 and 14.
Wessel's German patent application No. 2 220 815 relates to another suction head of this type. The following description made with reference to FIG. 5 of the accompanying drawing relates solely to the items of the sole plate which distinguish the Wessel suction head from the Olivier suction head. The sole plate 24 has two substantially rectilinear longitudinal channels 25 and 26 which are separated by two ridge elements 30 having a passage 31 provided therebetween with the top horizontal wall thereof being situated at substantially the same level as the level of the channels. An aperture 32 is provided in said sole plate and extends across the front channel 26 into the passage 31 and just reaches the rear channel 25.
These prior art suction heads are unsuitable for picking up and vacuuming fibrous substances such as hairs or threads from a mat or carpet to which they may be attached in relatively large quantities after a sewing session or after a dog or an other hairy animal has been in the room.
Schwab's German patent application No. 2 100 465 describes a household implement for picking up and swallowing threads or hairs, etc. from mats, carpets, or the like to which they may have become attached. This implement may be a mechanical carpet sweeper having one or two rotary brushes, or else it may be a nozzle for a vacuum cleaner. The sweeper or the nozzle is fitted under its sliding surface with two pieces of padding which are covered with the above-mentioned cloth having oriented fibers. The padding is adapted to extend along the inlet openings in such a fashion that if the implement is a one-brush sweeper the padding is situated on either side of the longitudinal opening through which the brush acts; if the implement is a two-brush sweeper, the padding is placed between the longitudinal openings through which the brushes act; and if the implement is the nozzle of a vacuum cleaner, the padding is disposed on either side of the very deep longitudinal opening which is connected to the suction tube. In each case, the sloping fibers on one of the pieces of padding are directed forwardly and on the other piece of padding they are directed rearwardly, with the pieces of padding being located so that the fibers are simultaneously directed towards the common opening or towards the two openings.
A Schwab suction nozzle fitted in this way has already been exploited commercially, thereby showing up its advantages and its drawbacks.
The advantage of such equipment lies in its effectiveness in extracting hairs or threads from carpets, with greater efficiency than the above-mentioned prior suction heads.
However, a first drawback of the Schwab's equipment lies in abnormal wear of the carpet under prolonged use, and also in poor suction of the threads or hairs and of the dust picked up from the carpet. As a result it is necessary to have both the Schwab equipment and a conventional suction head of the above-mentioned type available simultaneously, with the Schwab equipment being used rarely and solely for extracting threads and hairs from carpets, mats, etc. when the threads or hairs are present in relatively large quantities, while the prior suction head is used for removing dust from all kinds of floor, including carpeted floors.
A second drawback of the Schwab suction head lies in the fact that it is too difficult to move so that operating it is hard work and tiring, which can lead users making do without it. Further, demonstrators are well aware of this drawback, and to remedy it they raise the carpet to be treated so that the handle of the equipment is at a smaller angle than it would be in normal use, thereby making it considerably easier to operate.
The aim of the present invention is to remedy these drawbacks by improving a prior suction head of the above-mentioned type or of any other type having the same characteristics. The only requirement is that the sole plate has at least two longitudinal suction channels in communication with the suction tube via at least two openings constituted by two horizontal apertures or at least by one horizontal aperture and a vertical passage.